284 = 22 x 71.
284 is a number that cannot be written as a sum of three squares.
284 = 28 + 28.
284 and 220 form a pair of amicable numbers, the smallest amicable pair. Two numbers n and m are called an amicable pair if the sum of all positive divisors of n is equal to the sum of all positive divisors of m and both are equal to n + m.
